The E-expansion for QED

We study Quantum Electrodynamics in =3 (QED3) coupled to flavors of fermions. The theory flows to an IR fixed point for larger than some critical number . For ≤, chiral symmetry breaking is believed to take place. In analogy with the Wilson-Fisher description of the critical () models in =3, we use the existence of a fixed point in =4−2 to study the three-dimensional theory. We show how the -expansion can be used to study the anomalous dimension of 2- and 4-fermion operators. The latter leads to an estimate of the critical number . An important novelty compared to the () models is that, because of the structure of spinors, the theory in =3 has an enhanced symmetry. We identify the operators in =4−2 that correspond to the additional conserved currents at =3.